Fastening System for Large-Area Metal Roof Coverings or Wall Claddings

ABSTRACT

The invention relates to a fastening system for large-area roof coverings or wall claddings.The object is to create a fastening system which is structurally simple, consists of few parts, is fast to install and is suitable for high negative wind loads.Fastening is achieved within two upwardly projecting longitudinal ribs 2, which are formed by upwardly projecting sheet metal flanks 11. These sheet metal flanks 11 are bent up and provided with projections 13. According to the invention, T-shaped base bars 3 are disposed and fastened within the upwardly projecting longitudinal ribs 2, either continuously or only in some places. The horizontal wide limb of the T-shaped base bars 3, designated as foot limb 5, can be disposed upwardly or downwardly. The T-shaped base bar 3 has recesses 6 formed left and right in the vertical limb of the T-shaped base bar 3 and reaching into the foot limbs 5. Specially formed projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 engage in these recesses 6. These preformed projections 13 result in a form-fitting joint in conjunction with press plates 9 that can be disposed at or on the central limb 4. The press plates 9 are appropriately fastened with the base bar head 7 in a form-fitting manner or, for example, with screws. The press plates 9 are formed such that the press plates 9 span over the projections 13 of the sheet metal flanks 11 of the roof elements, sheet metal plates or sheet metal strips 1 positioned side by side. This creates a durable form-fitting joint by means of the T-shaped base bar 3 (or base element), central limb 4 and press plate 9. At the upper ends of the upwardly projecting lateral sheet metal flanks 11, the whole longitudinal rib is closed towards the top with a cover strip 12.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage of International ApplicationNo. PCT/162019/000411, filed on 2019 May 21. The internationalapplication claims the priority of DE 102018112135.0 filed on 2018 May19; all applications are incorporated by reference herein in theirentirety.

BACKGROUND

The invention relates to a fastening system for large-area metal roofcoverings or wall claddings for the fastening of sheet-like roofelements, sheet metal plates or sheet metal strips positionable side byside on roof or wall substructures, wherein the roof elements, sheetmetal plates or sheet metal strips may be designed flat, corrugated orprofiled.

With installed sheet metal strips positioned side by side or large-areasheet metal roof plates for roof coverings or wall claddings, on the onehand, fastening means that penetrate the roof covering should beabstained from, but on the other hand, there is a risk of suctioneffects caused by strong gusts of wind or gales, requiring securefastening of the roof covering on the underlying load-bearingsubstructure. However, the individual adjacent roof metal sheets mustallow gapless covering of roof or wall areas that may in part be verylarge, of different inclination and of different curvature. For specificroof shapes, this curvature alone may cause the suction effect to beadditionally reinforced in individual areas. The alternation betweenpositive and negative wind loads and temperature fluctuations introduceadditional loads. The requirements to the roof fastening are to keepunder control the effects of positive wind loads (pressure forces),negative wind loads (pull forces), expansions when heating up andcontraction when cooling down (thrust and shear forces) and still toensure tightness. Therefore, a construction and installation method hasgained acceptance, where the individual sheet metal strips or sheetmetal plates are held along longitudinal ribs on the roof covering ofthe roof or wall substructure. Various types of roof fastening areknown, where fastenings are used for safety reasons and which penetratethe roof covering at different locations spaced from each other, whichwill always result in problems of tightness of such roof or wallcoverings. This is therefore unsuitable for many roof and wallconfigurations and requires a high maintenance effort. Therefore, roofand wall coverings are preferred, which dispense with the need of roofpenetration. Generally, holders that are arranged inside are thereforeused, which are to fasten the roof covering reliably. These are arrangedat specific distances between each other, depending on the constructiontype. Therein, one sheet metal strip overlaps the next one, in order toproduce tightness. Such a technical solution is known from EP 0 530 483A1, where a roof covering is made by means of profiled metal strips laidside by side, wherein on one side an adjacent metal strip overlaps thenext metal strip in the same direction along a longitudinal rib shapedto protrude upwards. The metal strips are held on the roof substructureby means of different folding seams which are fastened in a hook shapedholder in a form-fitting manner to ensure sufficient fastening. However,this fastening solution requires sheet metal strips that are preformeddifferently. The fastening is done by a hook-shaped holder fastened tothe load-bearing substructure. As is general practice, it isscrew-fastened to the substructure. The hook-shaped holder can be ofvarious shapes. However, this method of fastening only allows a purelyform-fitting fastening of the sheet metal strips with the screw-fastenedholder located inside. Considering extended periods, the form-fittingjoint can bend open due to the various acting forces, and the strengthcan become so low that the individual sheet metal strips may well bestripped off in gales.

EP 204 123 B1 describes a modular system for a wall structure, whereplate-shaped façade structures can be snapped into a holding element andwhere flanges are disposed at a specific angle on each plate element atthe left and right, the free ends of which flanges are bent over suchthat this results in projections at the ends to engage with the recessesof a holding element. The holding element is screw-fastened with thesubstructure. This solution has the disadvantage that this form-fittingjoint can withstand high negative wind loads only to a limited extent,and furthermore, this façade structure is not watertight.

DE 199 41 510 A1 describes another roof covering of sheet metal stripspositioned side by side and which, when installed, are joined to eachother by longitudinal ribs that form and thereby also sealed. Forfastening, so-called holding strips are screw-fastened to the roofsubstructure. Left and right at the holding strip, upwardly protrudinghooks are arranged, whose head parts are bent over to one side in a hookshape. At the left and right, the sheet metal strips haveperpendicularly upright longitudinal ribs. One side of the sheet metalstrip engages the hook from below while the other side engages the headpart and the engaged longitudinal rib also in a hook-like manner, makingthe form-fitting joint. Here, too, the purely form-fitting joint, whichis not permanent in the long term and is also no secure heavy-dutyfastening, is also disadvantageous.

US 2009/0094921 A1 also describes a fastening system of another rooffastening, where the fastening to the roof substructure is achieved byupwardly projecting longitudinal ribs, with the ends of the upwardlyprojecting protruding sheet metal flanks of adjacent so-called tilesmutually engage and a standing seam is formed. In order to prevent thisform-fitting joint from widening up under load, clips are fastened tohave a kind of clamping effect. The problem here is that this kind offastening system does not stabilize the tiles (sheet metal strips)sufficiently and immobilize them because these are only fixed at theupper end of the standing seams and the tiles may therefore be deformedunder the forces acting in various ways. Here, the roof covering may beconsiderably deformed.

SUMMARY

The invention relates to a fastening system for large-area roofcoverings or wall claddings.

The object is to create a fastening system which is structurally simple,consists of few parts, is fast to install and is suitable for highnegative wind loads.

Fastening is achieved within two upwardly projecting longitudinal ribs2, which are formed by upwardly projecting sheet metal flanks 11. Thesesheet metal flanks 11 are bent up and provided with projections 13.According to the invention, T-shaped base bars 3 are disposed andfastened within the upwardly projecting longitudinal ribs 2, eithercontinuously or only in some places. The horizontal wide limb of theT-shaped base bars 3, designated as foot limb 5, can be disposedupwardly or downwardly. The T-shaped base bar 3 has recesses 6 formedleft and right in the vertical limb of the T-shaped base bar 3 andreaching into the foot limbs 5. Specially formed projections 13 of thesheet metal flanks 11 of the roof elements, sheet metal plates or sheetmetal strips 1 engage in these recesses 6. These preformed projections13 result in a form-fitting joint in conjunction with press plates 9that can be disposed at or on the central limb 4. The press plates 9 areappropriately fastened with the base bar head 7 in a form-fitting manneror, for example, with screws. The press plates 9 are formed such thatthe press plates 9 span over the projections 13 of the sheet metalflanks 11 of the roof elements, sheet metal plates or sheet metal strips1 positioned side by side. This creates a durable form-fitting joint bymeans of the T-shaped base bar 3 (or base element), central limb 4 andpress plate 9. At the upper ends of the upwardly projecting lateralsheet metal flanks 11, the whole longitudinal rib is closed towards thetop with a cover strip 12.

DETAILED DESCRIPTION

The object of the invention is to create a fastening system forlarge-area metal roof coverings or wall claddings for the fastening ofsheet-like roof elements, sheet metal plates or sheet metal stripspositionable side by side on roof or wall substructures, which isstructurally simple, consists of only few parts, is fast to install andis suitable for high negative wind loads.

The object is achieved by the characteristics of the first patent claim,according to the invention. Further purposeful embodiments of theinvention are the object of the further dependent claims. The fasteningsystem for large-area metal roof coverings or wall claddings accordingto the invention is suitable for the fastening of two or any number ofsheet-like roof elements, sheet metal plates or sheet metal stripspositionable side by side on roof or wall substructures, wherein theroof elements, sheet metal plates or sheet metal strips 1 may bedesigned differently, such as flat or corrugated or profiled. Fasteningis achieved within two upwardly projecting longitudinal ribs 2, whichare formed by sheet metal flanks 11 that project upwardly at the sides.These sheet metal flanks 11 are preferably bent up at a right angle,however, other angles (obtuse or acute) are also conceivable. Thelongitudinal ribs 2 can be parallel or at an angle to each other on thecovering and are distributed over the roof covering or wall cladding.According to the invention, the roof or wall substructure has T-shapedbase bars 3 disposed and fastened within the upwardly projectinglongitudinal ribs 2, either continuously or only in some places (thendesignated as base elements). The horizontal wide limb of the T-shapedbase bars 3 (or base elements), designated as foot limb 5, can bedisposed upwardly or downwardly. The T-shaped base bar 3 has recesses 6formed on the left and right in the vertical limb of the T-shaped basebar 3, designated as central limb 4, and reaching into the foot limbs 5.Specially formed projections 13 of the lateral sheet metal flanks 11 ofthe roof elements, sheet metal plates or sheet metal strips 1 engage inthese recesses 6. This preformed projections 13 result in a form-fittingjoint in conjunction with press plates 9 that may be disposed at or onthe central limb 4. The press plates 9 are generally disposed inmultiple numbers at specific intervals. However, it is also possiblethat they are formed as continuous bar-like press plates 9. The pressplates 9 are fastened with the base bar head 7 in a suitableform-fitting manner or, for example, screw-fastened. A cohesive joint isalso possible for specific roof coverings. The press plates 9 are formedsuch that press plates 9 span over the projections 13 of the sheet metalflanks 11 of the roof elements, sheet metal plates or sheet metal strips1 positioned side by side. This creates a durable form-fitting joint bymeans of the T-shaped base bar 3 (or if distributed in pieces, to bedesignated a base element), central limb 4 and press plate 9. At theupper ends of the upwardly projecting lateral sheet metal flanks 11, thewhole longitudinal rib is closed towards the top with a cover strip 12.

A particularly durable, permanent, form-fitting joint between the roofelements, sheet metal plates or sheet metal strips 1 and the T-shapebase bar or the T-shaped base element 3 with its central limb 4 and thefoot limbs 5 in the fastening system for large-area metal roof coveringsor wall claddings is achieved if the dimensions and shapes of theprojections 13 in the sheet metal flanks 11 correspond with thedimensions and shapes of the recesses 6 in the central limb 4 and in thefoot limbs 5. The dimensions and shapes of the press plates 9 arepreferably also matched with the dimensions and shapes of theprojections 13.

It is of considerable advantage if the two recesses 6 in the centrallimb 4 and in the foot limbs 5 are symmetrical in the fastening systemfor large-area metal roof coverings or wall claddings. Then the roofelements, sheet metal plates or sheet metal strips 1 with the preformedprojections 13 and sheet metal flanks 11 can be formed identically atthe left and right (also symmetrical). This offers considerable savingsof time and costs already when manufacturing the preformed roofelements, sheet metal plates or sheet metal strips 1. In addition, themounting position is then not predefined, resulting in advantages duringthe roof or wall installation at the site.

In the fastening system for large-area roof coverings or wall claddings,different shapes of the recesses 6 and corresponding projections 13 canadvantageously be used. Thus, the two recesses 6 in the central limb 4and in the foot limbs 5, including the shape of the press plate 9, maybe formed as a dovetail, oval or circular cross-section in the pressurearea.

In a simple manner, the security against negative wind loads can beconsiderably improved if the fastening system for large-area roofcoverings or wall claddings additionally has reinforcement bars 14disposed in the projections 13 of the sheet metals flanks 11. Thesereinforcement bars 14 are inserted from the front side into theprojections 13 or are pre-inserted. Preferably, the cross-sections ofthe reinforcement bars 14 are matched with the cross-sections of theprojections 13. This prevents the relatively thin-walled sheet metalroof elements, sheet metal plates or sheet metal strips 1 from deformingwith time under the acting forces and the form-fitting joint from beinglost. It is also conceivable that the cross-sections differ from eachother. Thus, triangular or quadrangular cross-sections of thereinforcement bars 14 are conceivable, for example. Using thereinforcement bars results in a force-locking joint that cannotdisengage by itself. Furthermore, the reinforcement bars 14 have theeffect that the stability of the whole roof between the longitudinalribs 2 improves considerably. There will hardly be any deformations inthe whole roof covering. The roof covering is almost immediately fixedand tensioned mechanically on the roof and wall substructure, retainingits position and shape relative to the roof substructure because theform-fitting joint cannot be bent open.

In the fastening system for large-area roof coverings or wall claddingsaccording to the invention, the form-fitting joint is most secure andstable if the dimensions and the cross-sectional shape of thereinforcement bars 14 are precisely matched with the dimensions andcross-sectional shape of the projections 13 of the sheet metal flanks 11and also with the cross-sectional shape of the recesses 6.

Instead of a form-fitting joint of the press-plates 9 with the base barhead 7 in the fastening system for large-area roof coverings or wallcladdings, the press plates 9 fastened to the central limb 4 can also befastened at suitable intervals to the base bar head 7 in a force-lockingmanner by headed screws 10, which are inserted at specific intervalsdepending on the load.

In the fastening system for large-area roof coverings or wall claddings,the T-shaped base bars 3 or the T-shaped base elements 3 can be fastenedto the roof or wall substructure by means of accordingly dimensionedbase screws 8, arranged in a staggered or pairwise manner, for reasonsof strength.

In the fastening system for large-area roof coverings or wall claddings,it is of advantage if the T-shaped base bars 3 and/or the press plates 9are designed as profile rails. The T-shaped base bar 3 or also the pressplates 9 may be disposed in sections with spaces between them or, forreasons of strength and stability, also continuously along the wholeextension of the roof, i.e. extending without any gap.

To provide for reliable sealing against weathering effects, specificallyagainst any humidity, the fastening system for large-area roof coveringsor wall claddings has continuous cover strips 12 joined to the top ofthe longitudinal ribs 2 by means of a form-fitting folded seam joint.

For specific wider designs of the longitudinal ribs, the fasteningsystem for large-are roof coverings or wall claddings may have theT-shaped base bars 3 or T-shaped base elements 3 with the press plates 9in an inverse position and fastened to the roof or wall substructure bymeans of central through-going fastening screws 15.

Depending on the construction and material of the respective roofcovering, the reinforcement bars 14 of the fastening system forlarge-area roof coverings or wall claddings may optionally be made ofstainless steel, aluminium or also of various plastic materials, throughto rubber materials or fabric composites.

It may also make sense if the additional reinforcement bars 14 of thefastening system for large-area wall coverings or wall claddings aremade of different materials. For example, a plastic sheath cancompensate different expansions and frictions between metalreinforcement bars 14 and the metal sheet of the roof covering.

To prevent the reinforcement bars 14 in this fastening system fromslipping out of projections 13, particularly in the case of steeplarge-area wall coverings or vertical wall claddings, the reinforcementbars 14 may be designed with linear, helical or locally disposedprotrusions 17. This causes them to grip into the surface within theprojections of the respective roof material.

In the fastening system for large-area wall coverings or wall claddings,it is also possible to draw in continuous ropes into the projections 13,instead of the inserted reinforcement bars 14. As needed, thesecontinuous ropes can be clamped taut at each end and the whole roofcovering can thus be specially tied down and fixed to the roof or wallstructure. Furthermore, the ropes can be drawn in under tension(stretched), with the cross-section of such ropes expanding again afterrelaxation and filling the space of recess 6 completely. Both steel andother permanent weatherproof rope types are suitable. Thus, for example,the ropes may be made of plastic materials or carbon fibres, whereinthese may additionally be impregnated with curable synthetics resins.

The fastening system for large-area metal roof coverings or wallcladdings using upwardly projecting longitudinal ribs 2 ensures safe,stable, storm-proof fastening of sheet-like roof elements, sheet metalplates or sheet metal strips 1 positionable side by side, both on roofsof various inclinations and curvatures and on inclined, vertical oroverhanging wall structures, and it is also tight against any climaticinfluences. It consists of few structurally different individualelements, is cost-saving, fast to install and can be designed for veryhigh negative wind loads. In addition, the non-negligible pull and shearforces acting on large coverings, caused for example by thermalexpansions are reliably compensated without damage.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention shall be explained in detail in one exemplary embodimentby reference to FIGS. 1 to 4.

FIG. 1 shows the cross-section through a fastening system according tothe invention within a longitudinal rib 2 with pairwise screw fasteningof the T-shaped base bar 3 to a roof or wall substructure (not drawn).

FIG. 2 shows a fastening system with inserted reinforcement bars 14.

FIG. 3 shows a fastening system with a screw-fastened press plate 9having a specially designed base element head 7.

FIG. 4 shows a wide design with a T-shaped base bar 3 arranged in topposition and screw-fastened in a through hole and secured by means of apair of inserted reinforcement bars 14 having protrusions 17 on them.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the cross-section through a preferred embodiment of afastening system according to the invention within a longitudinal rib 2with symmetric pairwise screw-fastening by two base screws 8 of theT-shaped base bar 3 on a roof or wall substructure not depicted in thedrawing. The base bar head 7 as the end of the central limb 4 of theT-shaped base bar 3 is complementary to a connection recess with aT-shaped undercut in the press plate 9, also designed in a T-shape. TheT-shaped base bar 3 is screw-fastened to the roof or wall substructurewith its wide upper bar down. The large upper bar then forms the leftand right foot limbs 5 which are recessed in an almost semi-circularshape. The central limb 4 is straight and the base bar head 7 isT-shaped. Instead of the T-shaped joining solution between the base barhead 7 and the press plate 9, a dovetail joint may be designed. This hasadvantages during installation because the press plate 9 is pushed overthe base bar head 7 from the front side. The press plate 9 also hasalmost semi-circular recesses formed left and right and open towards thebottom. In this way, an almost oval recess 6 is produced. After theT-shaped base bars 3 have been fastened to the roof or wall substructureusing the base screws 8, the two preformed roof elements, sheet metalplates or sheet metal strips 1 are inserted left and right into theT-shaped base bars 3. The roof elements, sheet metal plates or sheetmetal strips 1 are provided with almost oval projections 13 designed incontinuation to a double bend. This is of advantage, ensuring that thetwo flat portions of the left and right roof elements, sheet metalplates or sheet metal strips 1 can rest on the roof or wall substructureover the full flat area to the greatest possible extent.

As a rule, this is a beam, joist or girder construction because suchroof coverings are not installed on planar substructures. The shapes andpositions of the projections 13 correspond in their dimensions andcross-sections with the dimensions and cross-sections of the recesses 6.The roof elements, sheet metal plates or sheet metal strips 1 continueupwards as sheet metal flanks 11 that project upwardly at a right angle.When the roof elements, sheet metal plates or sheet metal strips 1 havebeen inserted into the T-shaped base bars 3 or base elements, the pressplates 9 are slid onto them in a suitable manner from the front side.When the roof elements, sheet metal plates or sheet metal strips 1 arenow fixed within the longitudinal ribs 2, a continuous cover strip 12 isinstalled at the upper end of the sheet metal flanks 11 by making afolding seam. This is done automatically by means of a suitable foldingmachine. The longitudinal rib 2 is thereby closed in a climate-proofmanner and a permanent, mechanically secure fastening to the roof orwall substructure is produced.

FIG. 2 shows an equivalent embodiment of a fastening system forlarge-area metal roof coverings or wall claddings, as already describedabove in FIG. 1. However, reinforcement bars 14 are additionallyinserted or slid into the recesses 6 left and right. For particulardesigns of the roof coverings, it may be sufficient that a reinforcementbar 14 is inserted or slid in only on one side. Here, thesereinforcement bars 14 are almost of an oval design and their dimensionsand cross-sections correspond with the projections 13 of the roofelements, sheet metal plates or sheet metal strips 1. This improves thestrength of the construction considerably. Depending on the dimensioningof the reinforcement bars 14, the mechanical stability at the bottom inthe area of the stable roof or wall substructure can be freely adjustedby appropriately larger or smaller cross-sections being pre-inserted orslid in posteriorly. Thus, the security against negative wind loads isconsiderably improved. Preferably the cross-sections of thereinforcement bars are matched with the cross-sections of theprojections 13. This prevents the relatively thin-walled sheet metalroof elements, sheet metal plates or sheet metal strips from deformingwith time under the acting forces and the form-fitting joint from beinglost. The replacement bars 14 produce a force-locking, permanent jointimmediately in the area of the planar roof covering (roof tile).

FIG. 3 shows a fastening system for large-area metal roof coverings orwall claddings for fastening sheet-like roof elements, sheet metalplates or sheet metal strips 1 positionable side by side in anembodiment with screw-fastening of the press-plate 9 with a base elementhead 7 specially shaped for screw-fastening. All other design detailsare equivalent to the technical embodiment as described under FIG. 1.Here, the base bar head 7 is specially reinforced and enlarged andinside a cavity is disposed such that, here for example, the pressplates 9 are simply joined with the T-shaped base bar 3 via the centrallimb 4 using a self-tapping headed screw 10. This base bar is in turnfastened to the roof or wall substructure not shown by means of twoself-tapping base screws 8 used in pair. This advantageous embodimentcan be installed faster on the site because the press plates 9 need notbe slid in from the front side but can be fitted and screw-fastened fromthe top.

FIG. 4 shows a wider embodiment of a fastening system for large-arearoof coverings or wall claddings. In this case, the T-shaped base bar 3and the press plate 9 are in an inverse arrangement as compared with theprevious arrangements, i.e. the press plate 9 is disposed at the bottomdirectly on the roof or wall substructure. Then the preformed roofelements, sheet metal plates or sheet metal strips 1 are placed togetherwith pre-inserted reinforcement bars 14, then the T-shaped base bar 3 isinserted from the top and screw-fastened to the roof or wallsubstructure together with press plate 9 underneath by means of athrough-going fastening screw 15. To improve the stability of this wideroof covering embodiment, two reinforcement bars 14 are inserted hereagain on the left and right. These may be slid in posteriorly, but aregenerally already inserted before the T-shaped base bars 3 are insertedin and fastened to the projections 6 of the roof elements, sheet metalplates or sheet metal strips 1. Thus, the negative wind loads or otheracting forces cannot lead to any deformations of the roof covering androof tiles. The reinforcement bars 14, which are made of two materialshere, have special protrusions 17 gripping into the material of the roofelements, sheet metal plates or sheet metal strips 1 and permanentlypreventing slippage of the reinforcement bars 14. The technical solutiondescribed above is primarily usable as a fastening system for large-areametal roof coverings or wall claddings for the fastening of sheet-likeroof elements, sheet metal plates or sheet metal strips positionableside by side on roof or wall substructures.

LIST OF REFERENCE NUMERALS

-   1 Roof elements, sheet metal plates or sheet metal strips-   2 Longitudinal ribs-   3 T-shaped base bars, base elements-   4 Central limb-   5 Foot limb-   6 Recesses-   7 Base bar head-   8 Base screws-   9 Press plates-   10 Headed screw-   11 Sheet metal flank-   12 Cover strip-   13 Projections-   14 Reinforcement bars-   15 Through-going fastening screw-   16 Folded seam joint-   17 Protrusions

1. A fastening system for large-area metal roof coverings or wallcladdings for the fastening of sheet-like roof elements, sheet metalplates or sheet metal strips positionable side by side on roof or wallsubstructures, wherein the roof elements, sheet metal plates or sheetmetal strips are designed flat or corrugated or profiled, fastened bymeans of upwardly projecting longitudinal ribs formed by upright sheetmetal flanks and the longitudinal ribs are distributed across the roofcovering or wall cladding in parallel or at an angle relative to eachother, characterized in that T-shaped base bars (3) are disposed andfastened in a longitudinal direction within the upwardly projectinglongitudinal ribs (2) on the roof or wall substructure, recesses (6) areformed in the T-shaped base bars (3) left and right on the central limbs(4) and reach down to the foot limbs (5), projections (13) of the sheetmetal flanks (11) of the roof elements, sheet metal plates or sheetmetal strips (1) engage in these recesses (6), press plates (9) arefastened to the central limb (4), with the press plates (9) spanningover the projections (13) of the sheet metal flanks (11) of the roofelements, sheet metal plates or sheet metal strips (1) positioned sideby side and the sheet metal flanks (11) along the longitudinal ribs (2)being closed towards the top using a cover strip (12).
 2. The fasteningsystem for large-area roof coverings or wall claddings according toclaim 1, characterized in that the dimensions and shape of theprojections (13) in the sheet metal flanks (11) correspond with thedimensions and shapes of the recesses (6) in the central limb (4) and inthe foot limbs (5) of the T-shaped base bars (3).
 3. The fasteningsystem for large-area roof coverings or wall claddings according toclaim 1, characterized in that the two recesses (6) in the central limb(4) and in the foot limbs (5) are formed symmetrically.
 4. The fasteningsystem for large-area roof coverings or wall claddings according toclaim 1, characterized in that the two recesses (6) in the central limb(4) and in the foot limbs (5) are formed as a dovetail, oval or circularcross-section.
 5. The fastening system for large-area roof coverings orwall claddings according to claim 1, characterized in that reinforcementbars (14) are additionally disposed in the projections (13) of the sheetmetal flanks (11).
 6. The fastening system for large-area roof coveringsor wall claddings according to claim 5, characterized in that thedimensions and the cross-sectional shape of the reinforcement bars (14)are matched with the dimensions and cross-sectional shape of therecesses (13) of the sheet metal flanks (11) and of the press plates(9).
 7. The fastening system for large-area roof coverings or wallcladdings according to claim 1, characterized in that press plates (9)fastened to the central limb (4) are screw-fastened to the base bar head(7) at appropriate intervals by means of headed screws (10).
 8. Thefastening system for large-area roof coverings or wall claddingsaccording to claim 1, characterized in that the T-shaped base bars (3)are fastened with the roof or wall substructure by means of base screws(8) arranged in a staggered or pairwise manner.
 9. The fastening systemfor large-area roof coverings or wall claddings according to claim 1,characterized in that the T-shaped base bars (3) and/or the press plate(9) are formed as profile rails.
 10. The fastening system for large-arearoof coverings or wall claddings according to claim 1, characterized inthat the cover strip (12) is joined to the sheet metal flanks (11) bymeans of a form-fitting folded seam oint.
 11. The fastening system forlarge-area roof coverings or wall claddings according to claim 1,characterized in that the T-shaped base bars (3) and the press plates(9) are disposed inversely and both are fastened to the roof or wallsubstructure by means of a central through-going fastening screw (15).12. The fastening system for large-area roof coverings or wall claddingsaccording to claim 1, characterized in that the reinforcement bars (14)consist of stainless steel, aluminium, plastic materials or rubbermaterials.
 13. The fastening system for large-area roof coverings orwall claddings according to claim 1, characterized in that thereinforcement bars (14) are formed of different materials.
 14. Thefastening system for large-area roof coverings or wall claddingsaccording to claim 1, characterized in that the reinforcement bars (14)are formed with linear, helical or locally disposed protrusions (17).15. The fastening system for large-area roof coverings or wall claddingsaccording to claim 1, characterized in that instead of the insertedreinforcement rods (14), continuous ropes or ropes drawn in undertension and relaxing into place are disposed.